Study of Thermostable Chitinase Isolated and Purified from Oryctes rhinoceros Larvae Gut

A chitinase-producing bacteria was locally isolated from rhinoceros beetle (Oryctes rhinoceros) larvae gut discovered in mushroom compost. A strain was selected from the source and labeled as RBLG1. It was identified using 16s rDNAsequencing and has strong homology to Bacillus cereus. Chitinase produced from RBLG1 was purified using ammonium sulfate precipitation, ion exchange chromatography, and gel filtration. The purified chitinase from RBLG1 shows the homogeneity 1.9 fold after the gel filtration process. The purified chitinase was identified and analyzed using SDS-PAGE and the molecular mass from the strain was approximately 40 kDa. Further assays were performed to study the effect of temperature, pH, and metal ion on the purified enzyme. The purified enzyme shows highest chitinase activity at pH 4 and 60 °C. For metal ion test, chitinase from RBLG1 was unaffected when treated by various ions. Kinetic performance of chitinase using Michaelis-Menten equation shows Km and Vmax values were 2.3 mM and 0.0294 [P] mM/min, respectively.

Simultaneously vanishing higher derived limits

In 1988, Sibe Mardešić and Andrei Prasolov isolated an inverse system $\textbf {A}$ with the property that the additivity of strong homology on any class of spaces which includes the closed subsets of Euclidean space would entail that $\lim ^n\textbf {A}$ (the nth derived limit of $\textbf {A}$ ) vanishes for every $n>0$ . Since that time, the question of whether it is consistent with the $\mathsf {ZFC}$ axioms that $\lim ^n \textbf {A}=0$ for every $n>0$ has remained open. It remains possible as well that this condition in fact implies that strong homology is additive on the category of metric spaces. We show that assuming the existence of a weakly compact cardinal, it is indeed consistent with the $\mathsf {ZFC}$ axioms that $\lim ^n \textbf {A}=0$ for all $n>0$ . We show this via a finite-support iteration of Hechler forcings which is of weakly compact length. More precisely, we show that in any forcing extension by this iteration, a condition equivalent to $\lim ^n\textbf {A}=0$ will hold for each $n>0$ . This condition is of interest in its own right; namely, it is the triviality of every coherent n-dimensional family of certain specified sorts of partial functions $\mathbb {N}^2\to \mathbb {Z}$ which are indexed in turn by n-tuples of functions $f:\mathbb {N}\to \mathbb {N}$ . The triviality and coherence in question here generalise the classical and well-studied case of $n=1$ .

Homology of labial chaetae in Entomobryoidea (Collembola)

The labium in Collembola consists of three parts (Folsom 1899): labial palp, basomedian (submentum) and basolateral (mentum) fields. Labial chaetotaxy, i.e. number, nature and relative position of chaetae, has been one of the standard descriptive components for species diagnoses in Entomobryoidea. Labial palp, including labial papillae, guard chaetae and proximal chaetae, has been well investigated across major collembolan lineages by Fjellberg (1999). For the chaetae behind the labial palp (mentum and submentum, Figs 1‒2) in Entomobryoidea, Gisin (1964) introduced the nomenclature of a1‒a5 for the anterior row and M1M2rEL1L2 for the posterior row in Lepidocyrtus; the lowercase letter r represented a smaller chaeta between M and E. Later, Gisin (1967) applied this system to Pseudosinella but defined uppercase and lowercase letters as ciliate and smooth chaetae, respectively. Chen & Christiansen (1993) mostly followed Gisin’s nomenclature but named the anterior row as A, B, C, D and F. When there was more than one chaeta inner to R, M-series, they were designated as M1, M2, Ms (supplementary) etc. Smooth chaeta r was sometimes named as ‘v’ (vestigial) in Lepidocyrtinae when it was very tiny. Because the degree of plurichaetosis on submentum greatly differs among Entomobryoidea species, homology of basomedian chaetae may be incorrectly recognized in adults. In this study, we observed labial chaetotaxy (guard chaetae of labial palp excluded) of early instars in twenty species, clarified their homologies and unified the nomenclature systems.

Coronavirus ORF1ab Polyprotein Associated Nsp16 Protein is a RlmE Methyltransferase and May Methylate 21S Mitochondrial rRNA of Most Mells Inhibiting Protein Synthesis

Covid-19 infections are rapidly spreading worldwide with more than 100000 death and thus understanding the molecular mechanism of tropism of human cells is an urgent need for drug design. We have described here a bioinformatics approach to predict the functional aspects of non-structural nsp16 protein of Corona virus. The covid-19 7098 AA large polyprotein was degraded into sixteen proteins and last nsp16 protein was found an RlmE type rRNA methyltransferase. Nsp16 has no similarity to bacterial RlmABCD but has 25 percent similarity to the bacterial RlmE protein which methylates the U2551 2-hydroxy group of Ribose. The nsp16 proteins of different corona viruses like covid-19, bat-coronavirus, SARS and MERS have strong homology. Mrm2 and Dim1 like yeast and mammalian rRNA methyltransferases have 26-33 percent homologies but not with 2-O-capping MTase as reported previously. Rrp8 MTases also has no similarity to nsp16. We postulated that mitochondrial rRNA methylation of bronchial cells were mediated by the nsp16 protein causing inhibition of protein synthesis due to poor assembly of aminoacyl-tRNA or mRNA and peptidyl transferase at the PTC. This is one of the new molecular mechanism of corona virus cellular tropism and different than ACE-2 mediated blockage of cellular signalling to inhibit aldesterone biosynthesis with abnormal Na+ ions in cells. We also designed primers based on nsp16 cDNA sequence (nt 20659-21552, accession no MT121215) specific for Covid-19 diagnosis by RT-PCR.

Identification of a Pangolin Niche for a 2019-nCoV-like Coronavirus via an Extensive Meta-metagenomic Search

In numerous instances, tracking the biological significance of a nucleic acid sequence can be augmented through the identification of environmental niches in which the sequence of interest is present. Many metagenomic datasets are now available, with deep sequencing of samples from diverse biological niches. While any individual metagenomic dataset can be readily queried using web-based tools, meta-searches through all such datasets are less accessible. In this brief communication, we demonstrate such a meta-meta-genomic approach, examining close matches to the Wuhan coronavirus 2019-nCoV in all high-throughput sequencing datasets in the NCBI Sequence Read Archive accessible with the keyword “virome”. In addition to the homology to bat coronaviruses observed in descriptions of the 2019-nCoV sequence (F. Wu et al. 2020, Nature, doi.org/10.1038/s41586-020-2008-3; P. Zhou et al. 2020, Nature, doi.org/10.1038/s41586-020-2012-7), we note a strong homology to numerous sequence reads in a metavirome dataset generated from the lungs of deceased Pangolins reported by Liu et al. (Viruses 11:11, 2019, http://doi.org/10.3390/v11110979). Our observations are relevant to discussions of the derivation of 2019-nCoV and illustrate the utility and limitations of meta-metagenomic search tools in effective and rapid characterization of potentially significant nucleic acid sequences.ImportanceMeta-metagenomic searches allow for high-speed, low-cost identification of potentially significant biological niches for sequences of interest.

Learning from the Past: Possible Urgent Prevention and Treatment Options for Severe Acute Respiratory Infections Caused by 2019-nCoV

With the current trajectory of the 2019-nCoV outbreak unknown, public health and medicinal measures will both be needed to contain spreading of the virus and to optimize patient outcomes. While little is known about the virus, an examination of the genome sequence shows strong homology with its more well-studied cousin, SARS-CoV. The spike protein used for host cell infection shows key nonsynonymous mutations which may hamper efficacy of previously developed therapeutics but remains a viable target for the development of biologics and macrocyclic peptides. Other key drug targets, including RdRp and 3CLpro, share a strikingly high (>95%) homology to SARS-CoV. Herein, we suggest 4 potential drug candidates (an ACE2-based peptide, remdesivir, 3CLpro-1 and a novel vinylsulfone protease inhibitor) that can be used to treat patients suffering with the 2019-nCoV. We also summarize previous efforts into drugging these targets and hope to help in the development of broad spectrum anti-coronaviral agents for future epidemics.

Learning from the Past: Possible Urgent Prevention and Treatment Options for Severe Acute Respiratory Infections Caused by 2019-nCoV

With the current trajectory of the 2019-nCoV outbreak unknown, public health and medicinal measures will both be needed to contain spreading of the virus and to optimize patient outcomes. While little is known about the virus, an examination of the genome sequence shows strong homology with its more well-studied cousin, SARS-CoV. The spike protein used for host cell infection shows key nonsynonymous mutations which may hamper efficacy of previously developed therapeutics but remains a viable target for the development of biologics and macrocyclic peptides. Other key drug targets, including RdRp and 3CLpro, share a strikingly high (>95%) homology to SARS-CoV. Herein, we suggest 4 potential drug candidates (an ACE2-based peptide, remdesivir, 3CLpro-1 and a novel vinylsulfone protease inhibitor) that can be used to treat patients suffering with the 2019-nCoV. We also summarize previous efforts into drugging these targets and hope to help in the development of broad spectrum anti-coronaviral agents for future epidemics.

Structural and functional analyses of the N-terminal domain of the A subunit of aBacillus megateriumspore germinant receptor

Germination ofBacillusspores is induced by the interaction of specific nutrient molecules with germinant receptors (GRs) localized in the spore’s inner membrane. GRs typically consist of three subunits referred to as A, B, and C, although functions of individual subunits are not known. Here we present the crystal structure of the N-terminal domain (NTD) of the A subunit of theBacillus megateriumGerK3GR, revealing two distinct globular subdomains bisected by a cleft, a fold with strong homology to substrate-binding proteins in bacterial ABC transporters. Molecular docking, chemical shift perturbation measurement, and mutagenesis coupled with spore germination analyses support a proposed model that the interface between the two subdomains in the NTD of GR A subunits serves as the germinant binding site and plays a critical role in spore germination. Our findings provide a conceptual framework for understanding the germinant recruitment mechanism by which GRs trigger spore germination.

Transcriptomic evidence that von Economo neurons are regionally specialized extratelencephalic-projecting excitatory neurons

Abstractvon Economo neurons (VENs) are bipolar, spindle-shaped neurons restricted to layer 5 of human frontoinsula and anterior cingulate cortex that appear to be selectively vulnerable to neuropsychiatric and neurodegenerative diseases, although little is known about other VEN cellular phenotypes. Single nucleus RNA-sequencing of frontoinsula layer 5 identified a transcriptomically-defined cell cluster that contained VENs, but also fork cells and a subset of pyramidal neurons. Cross-species alignment of this cell cluster with a well-annotated mouse classification shows strong homology to extratelencephalic (ET) excitatory neurons that project to subcerebral targets. This cluster also shows strong homology to a putative ET cluster in human temporal cortex, but with a strikingly specific regional signature. Together these results predict VENs are a regionally distinctive type of ET neuron, and we additionally describe the first patch clamp recordings of VENs from neurosurgically-resected tissue that show distinctive intrinsic membrane properties relative to neighboring pyramidal neurons.